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81.
82.
The crude aqueous ethanol extract of the cones of Alnus glutinosa (L.) Gaertn. (Betulaceae; black alder, European alder) was obtained and further partitioned between water and various organic phases. The active water and butanol phases were subjected to assay-guided (DPPH) fractionation using repetitive RP HPLC until individual compounds were isolated. Their antioxidative activities, measured as SC?? values, were evaluated. The chemical structures of the isolated compounds were elucidated with the help of mass spectroscopy, (1)H NMR technique, UV spectroscopy, and chemical approaches. One novel ellagitannin, glutinoin (2), along with two known compounds, pedunculagin (1) and praecoxin D (3), were isolated and found to contribute to antioxidative activity of the A. glutinosa cones extract. The activities (SC??) of 1-3 were evaluated as 0.95 (1), 1.00 (2) and 1.01?μg?mL?1 (3). The scavenging effects of glutinoin (2) and praecoxin D (3) were reported for the first time. 相似文献
83.
Poumale HM Awoussong KP Randrianasolo R Simo CC Ngadjui BT Shiono Y 《Natural product research》2012,26(8):749-755
In addition to lupeol (1a), three long-chain alkanoic acid esters of lupeol, in which two were new, were isolated from the hexane and ethyl acetate twigs extract of Dorstenia harmsiana Engl. (Moraceae). The structures of the new compounds were elucidated on the basis of 1D and 2D NMR experiments. Some isolated compounds were evaluated for their antimicrobial activities. The lupeol and its three long-chain alkanoic acid esters showed antifungal and antibacterial activities. 相似文献
84.
Mridul Kanti Mandal Kentaro Yoshimura Lee Chuin Chen Zhan Yu Tadao Nakazawa Ryohei Katoh Hideki Fujii Sen Takeda Hiroshi Nonami Kenzo Hiraoka 《Journal of the American Society for Mass Spectrometry》2012,23(11):2043-2047
We have examined several combinations of solvents with the aim of optimizing the ionization conditions for molecular diagnosis of malignant tumours by PESI-MS. Although the best conditions may depend on the actual species in the sample, the optimal conditions for renal cell carcinoma (RCC) were achieved by using alcohols. PESI-MS successfully delineated the differential expression of phospholipids (PCs) and triacylglycerols (TAGs) in noncancerous and RCC tissues by using these solvent systems. This study paves the way for the application of PESI-MS in medical samples. 相似文献
85.
86.
87.
Hiroshi Maruyama Masao Shiozaki Sadao Oida Tetsuo Hiraoka 《Tetrahedron letters》1985,26(37):4521-4522
Base treatment of N-propargyl epoxyamide 5 afforded the acetylenic 3-(hydroxyethyl)-2-azetidinone 9a, which was subsequently transformed to phenyl thiolester 2, a versatile intermediate for the carbapenem synthesis. 相似文献
88.
T. J. Chuang H. Hiraoka A. Mödl 《Applied Physics A: Materials Science & Processing》1988,45(4):277-288
The photoetching behavior of poly(methylmethacrylate), poly(dimethylglutarimide) and chlorinated poly(methylstyrene) doped with pyrene and 4-aminobenzoylhydrazide excited by 308 nm excimer-laser pulses has been studied. Some common laser-etching characteristics including the reduction of the threshold fluence for ablation, the enhancement of etching efficiency and the existence of optimal conditions regarding the laser fluence and dopant concentration for generating clean and smooth etching patterns are identified. The photoetching mechanism and the potential application of the doping technique to material processing are discussed. 相似文献
89.
Chihiro Hiraoka Masaaki Matsuda Yuya Suzuki Shigeo Fujieda Mina Tomita Ken-ichi Fuhshuku Rika Obata Shigeru Nishiyama Takeshi Sugai 《Tetrahedron: Asymmetry》2006,17(24):3358-3367
Towards the synthesis of sterically hindered optically active secondary alcohol 2, yeast strains (Candida floricola IAM 13115 and Trichosporon cutaneum IAM 12206) with si-face hydride attack on isopropyl phenylsulfonylmethyl ketone 1 were developed by screening. Strains with complementary re-facial selectivity (Pichia angusta IAM 12895 and Pichia minuta IAM 12215) were also found. Based on the substrate specificity studies of these four strains, microbial reduction was applied to the synthesis of (3S,5S)-2,6-dimethyl-3,5-heptanediol 12a. 相似文献
90.
Abstract— Mechanism of the photogeneration of hydrogen peroxide and superoxide ion from tryptophan (Trp) and its photooxidation products was investigated. Near-ultraviolet irradiation of 3a-hydro-peroxypyrrolidinoindole, an intermediate in the photooxidation of Trp, has been shown to generate hydrogen peroxide efficiently under aerobic conditions. Irradiation of N-formylkynurenine in the presence of 3α-hydroxypyrrolidinoindole also produced hydrogen peroxide. The formation of superoxide ion in both reactions has been confirmed, whereas the reaction of Trp with chemically generated singlet oxygen did not produce any detectable amount of superoxide ion. 相似文献